Magnetic tachometer.



No. 823,237. 4 PATENTED JUNE l2, 1906. A. P. 6L C. H. WARNER. MA GNETIC' TAUHOMBTER.

kAPPLICATION Hup MAY 20,:1905.

2 SHEETS-SHEET 1.

Z WW I A mi l No. 823,237. PATENTED JUNE 12, i906. A. P. A; lG. H. WARNER. MAGNETIC TAGHOMBTBR.

"APPLICATION HLBD MAYzo. 1905.

2 SHEETS-SHEET 2.

UNITED sTATes CONSIN, lA CORPORATlON OF WlSUONSiN.

Specification of Letters Patei Application lediliayV Z, 1905. Serial No. 261,412.

.To all whom it m/y concern:

Be it known that we, ARTnUa P. iiilinnsa and CHARLES H. WARNER', citizens of the.

United States, residing at Beloit, in the county of Rock and State of Wisconsin, have invented a newand useful Magnetic Taclioni eter, of which the following is a specification.

This invention relates to magnetic ta'chometers and is designed as an improvement upon the magnetic tachomet'er set forth, described, end claimed in our' Patent No. 745,468, granted December l, 1903.

The' object of the invention` is to simplify and improve the construction of magnetic taclionieters and to rrender the saine more ellicient in operation.

A further object of our invention is to provide means in a magnetic tachomcler for automatically correcting the scale-reading for different temperatures.

A further object of the invention is to provide means for yieldingl y arresting the rotative movement of the scale-disl upon the completion of one revolution thereof.

Other obj ects of the invention will more fully hereinafter.

The invention `consists, substantially, in the app e ar construction, combination, location, and arrangement of parts, all as will be more fully hereinafter set forth, as shown in the accompanying drawings, and finali y pointed out in the appended claims.

Referring to the accompanying drawings, and to the various views andreference-signs appearing thereon, Figure 1 is a View inside elevation 'offen apparatus embed ying the principles of our invention. Fig. 2 is a view 1n central section on the line 2 2, Fig. 3, lool;- ing in the direction ofthe arrows. Fig. 3 is a View in plan onthe line 3 3, Fie. 2, looking in the direction ofthe arrows, the end cap being removed. Fig. 4 is a View in section on the line 4 4, Fig. 2, looking in the directioriof the arrows. Fig. 5 is a view in section on 'the line 5 5, F ig. 2, looking in the direction of the arrows. 6 is a broken detail View in section on the line 6 6, Fig. 3, looking iii the directionof the arrows. Fig. 7 is a broken detail view in plan, showing the yielding limit- Stop for the scale-disk. Fig. 8 'is a broken detail View in isection, showing means for pro erly a :semb ihg the easing.

lille same part is designated bythe same reference-sign i e it occiiis teiengiioot the several vieiifs. qi

in our prior phave shown, described, and ela' eter in which emcloyed a i fignetic mass inoii'ited for rela tion and an independen. disk interpose i between the m i f. mess, wher-shy when rotation is impatlie magnet e` revolvi g magnetic fiel i erateii or create-C71, te; to impart a tive movement to tie scale-dish a ext/enter de e proportionate to of rotation o w tft nar-` or the rotative moverne t i ing opposed suiteY of V'hudi is so proportion that the "eadin'y the sneed at which rotatirunning. The present in venion an apparatus of this g*- ieral i and resides specially features nient hereinafter to i) ed ont.

Referring to the accompany/ii reference-sign A de. .atea :i to receive and contain the part-s of eter. if..

Bilesignates a shaft erre into the casing and desig by the moving part, the s is of which is to be measure the device.

presented. lreariiwn blocks er p cooperating with snouiders former-i. on the end.

of a l;eaI'ingsle,eve il to form. racen/3. Y r

halls F, whereby .the shaft E is geurnaiecl witlnnu iialldfear. The bearing-sleeve u ,Q is exteriorly threaded to .'oe ieceivedin the interiin'ly-threaded hub-por" G of the ing A. i,lpon t' r clamped. a sleeve non-inegneilic in. i'led the magnet s'. form. of :i split ring ri ngedte in-:inse the sleeve ii, with the or poll-pieces en f slightly separated easi'i other, as cated at the point if, iglg. 4. if i received within the esse i. is @in i Lailiary o i-iupplcmentai cmsini il, comprising shell, and in the iorgitiiilin' center said s1 a pin-shaft iii, l f.

bearing-bloeit i .red oy the poi rien il* oi' ieg the auxiliary shell, and at'its opposite end ywith pin-shaft hl is the scaleydiskvi.

isf

a bearinpf-block P, carried in the center of the end wall` it of the auxiliary shell or casino. The rotative movement ol this pinesha'ft M 1s yieldingly opposed in any suitable or convenient manner-as, for instance, by means of a hair or watch spring S. Connected to rotate Suitably supported within the auxiliary shell or easing li is a magnetic mass B', preferably in the form of a closed ring. The arrangement is such that when rotation is limparted Ato shaft B a revolving magnetic lield is createdv in the space between the juxtaposed'surfaces of magnet J and magnetic mass B. Now by forming the scale-dish A of a suitable matcrial, preferably a material which is a conductor or' electricity, thereby forming an armature, a rotative tension is imposed upon said scale-dish, tending to rotate the same. .lhe

'rotary n'ioveinent or' the scale-disk, however,

is opposed by the tension of spring S, the tension or which may be so adjusted and ar ranged as that the scale-disk will be rotatively displaced through a distance proper-- 'monate to the speed at which the magnet J rotates, it being understoo l-that the scaledisk A. is interposed between the magnet J ansi the magnetic mass B. In order to prevent air-currents generated by the rotating part olt the tachometer aller-ting,r or influent` ing the rotative displacement of the scnlcf -disk, a shield may be interposed between the y scaledislr and the rotating part ol 'the tachometer. ln practice we employ lor this purpose a protecting shield or plate C', constitilting a bottom or l'loor for the auxiliaryY casing or shell L, and the central portion thereol", in. which the journal-stud N is mount ed, has been hereinabove referred to. In the side of the auxiliary shell or casingl and also in the side ol' the main casing A are formed openings (indicated at D) through which the scale-readings ol the scale-disk may be disvclosed, in practice the 'calibrations ol" the scale-disk being carried upon. the rinpr or llange portion olh such disk which enciiclcs the niegue/tic mass B.

As above ind' rated, the magnet J is in the lorm ol a split ring, with the ends or poles brought into close proximity with respect to each other. We have found this Afeature ol" .our invention most valuable and important, especially where the magnetic mass is in the form of a closed ring, for the reason that the magnet J is thereb)v made more permanent and is prevented from becoming demagnetized when revolved rapidly' and also renders the device less liable to' homme atlectcd bv.

outside electrical or magnetic influences, and hence the results accomplished are rendered more accurate. lh's feature of construction and arrangement, while well adapted. l'or use in" connection with tacliiometers,iis of equal value for use in the construction of electrical measuring and other devices, and we therefore do not desire tobe limited in respect te the use to which this combination is to be Ne have 'found in practice and in the prac tical operation of Imagnetic tachoineters el the. type and construction and character above referred to that by reason of' change of electrical yconductivity in the scale-diskv A, due to variations of the latn'iospheric tcmper ature, the scale-readings of the device are influenced and affected. lt is among the spen cial purposes of our present invention to provide `means vfor automatically correcting this defect, and according to the temperature itself and in. the accomplishment of this ebject we automatically vary in any suitable manner and according to the changes in. the atmospheric temperature the magnetic reluctance in the lield between the .magnet and mass. To this end we propose in one. form of our invention to support the magnetic mass B so as to permit the' opposed lace of said mass to approachnearer to or to recede farther from the cooperating opposed face ot' the magnet J, according to the temperature. This result may be accomplislied .in many specifically dilierent ways, and while wehave shown and will now describe `one arrangement for accomplishing this object we do not desire to be limited or restricted thereto. in the particular form shown we suspend or support the magnetic mass B l'rom the end piece or plate R ol the auxiliary shell or casing L by' means ol metallic strips D E. (See Figs. 2 and G.) of such metallic strips, the two strips of each set being' placed llatwisc upon each-other and braced or otherwise secured together and at one end to a portion oi' the end plate R, and at the other end said strips are brazed or otherwise secured to the magnetic massA B, said strips 'being bowed or foi-mod in the shape of leai-sprilngr strips, and in practice the strips D E are ol' dil'erent metals, having dill'erent coellicients of expansion. By this construction variations in the temperature will cause.

said suspending-strips to perform 'thelunction ol" a 'thermostat and will automatically vary. the distance between theopplosed faces of magnetic mass B and magnet J according to the lemperature so as to maintain unilorinity of magnetic condition in the lield which acts upon the scale-dish., Conse quen'tly the readings ol' the instrument are not distorted or impaired by-reason of any variation in the temperature, such variation being;r cmnpensatcd by the thermostatic supporting; or suspeiuiing;` strips D E. This we regard as a most important and 'valuable feature of our device.

The tcnsjion'o'l spriiug` S is so regulated as that the distance through which the scaledish is rotatively displaced is proportional to the speed. of rotation of the rotating partei the instrument. lt is important, however, to

In. practice we employ three sets IOC.

sed, tr sa... o-z .3111231131 Din,

. .L' am 5 1. 120 111.1. idw. .311-v n #110111 Yvewfc cmi in um. by 2.911.111..

ci.; 1111 d oir-M111( 1115-.....

f .cd

1' for 01:0., to be. limi. isbn-1I... showt.. an

. l 1&1

3. In a taeliometer, a magnet and. a magnetie mass, one ot'I these parts mounted te rotate, and means for supporting said parts for relative movement toward and. from j each other, said means operating according ."netic mass,'one of' these parts mounted to rotate, thermostatic strips suspending the other of said. parte in i'oximity to tlie rotating part, and a free y-rotative scale-disk interposed between said magnet and mass.

6. ln a taehometer, a magnet and a magnetic mass, one of tliese parte mounted to rotate, metallic strips arranged in sets,eacli set composed of strips of different metals', and forming a support for one of said parte,

and a scale-disk interposed between said parts.

7. In a taeiiometer, a magnet and a maglnetic mass, one of said parts being in tlie form of a split ring and the otlier inthe form of a closed ring, said parts mounted with their side surfaces or faces juxtaposed witlireference to each other, aiidfer relative rotation, and a scale-disk interposed between `the juxtaposed side surfaces or faces ol said parts.

8. AIn a taclioineter, a main case, a magnet lmounted Ytherein for rotative movement, an

auxiliary case, a magnetic mass mountedtlierein, said auxiliary ease adapted te be removably received within said main ease, means for yieldingly maintaining said aux- .iiiary ease within said main ease, and a seaie disk interposed between said magnet and mass.

9. in' a taeliometer, a main ease, a magnet' mounted to rotate therein, an auxiliary case removably mounted within said main case, said main case having a screw-top, a magnetic mass carried by said auxiliary ease, a scale-dislralso carried by said auxiliary case and. between said `magnet and. the magnetic mass, and awsprinplate bearing upon said auxiliary ease 4ain engaged by said screwtop to liold said auxiliary case in place.

10. ln a tacliometer, a magnet and a magnetic mass, one of these partel mounted to rotate, a scale-disk interposed between the magnet and. mass and mounted for free rotation, aiid means `for automatically `Varying tlie reluctance of the magnetic i'ield between said magnet and mass according to varia tions in the atmospheric temperature.

1i. 'The combination with a magnetic mass, amagnet in the form of a split ring.

with the ends or poles brought into close proximity, said magnet and mass arranged side by side and in parallel relation and an armature interposed between the juxtaposed sides or surfaces oi the mass and magnet, one of these parts mounted to rotate.

In Witness-whereof We have hereunto set our hands, this 10th day of' May, i905, in the presence of the subscribingr Witnesses.

ARTHUR P. WARNER. CHARLES H. WARNER.

1Witnesses:

Jas. BARCLM, A. S. Ko'ro. 

